Epibenthic Sled

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History
The epibenthic sled was designed by Dr. Robert Hessler of Scripps
Institute of Oceanography Howard Sanders and George R. Hampson of
the Woods Hole Oceanographic Institution (Hessler, Sanders 1966).
The net (1mm mesh) was specially designed plankton net made by William
Shoeder's (WHOI) daughter, Mrs. Ernest Case of N.J. She designed the
nets for both the small (4ft. long) and the larger epibenthic sleds
(7ft. long).

The larger 7-ft. sled was primarily designed for deep-sea sampling.
For the WHOI Sanders/Hessler project, we towed it at depths exceeding
5000 meters. The purpose was to collect rare deep-sea animals which
otherwise would be impossible to capture with grab samplers or box
cores. However, the epibenthic sled was considered to be less than
quantitative. Distances covered over the bottom can be estimated from
the ship's log to get an estimate of the area covered, however the
sled was never as accurate as the box corer for density determinations
of the macrofauna.

How It Works
A semi-quantitative bottom-sampling device is designed to trawl just
above the bottom at the sediment water interface (the epibenthic zone).
The sled occasionally (inadvertently) digs into the bottom, so an
infaunal sample is also collected. The sled is fitted with a 1mm mesh
net. The end of the sled is fitted with an extended removable cod
end, which served to provide the sled with a protected area where
the animals were not subjected to abrasion. Some cod ends were made
with 0.5mm mesh to retain smaller organisms.

A "front door" closing device was incorporated to retain the collected
sample inside the dredge to prevent washing while the dredge is being
brought to the surface. This spring-driven closing of the trawl was
activated by a timing devise designed by Benthos of North Falmouth.

The smaller (4 ft. long) sled has been used successfully for many
years to collect benthic organisms from local coastal waters.

Further Information
Some descriptions provided by George R. Hampson.

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